Synthesis of para-xylene and toluene
A method of making para-xylene or toluene is carried out by: (a) reacting a C5 or C6 linear monoene (itself, or formed from a C5 or C6 linear alkane) with a hydrogen acceptor in the presence of a hydrogen transfer catalyst to produce a C5 or C6 diene; (b) reacting the C5-C6 diene with ethylene to produce a cyclohexene having 1 or 2 methyl groups substituted thereon; and then (c) either (i) dehydrogenating the cyclohexene in the presence of a hydrogen acceptor with a hydrogen transfer catalyst to produce a compound selected from the group consisting of para-xylene and toluene, or (ii) dehydrogenating the cyclohexene in the absence of a hydrogen acceptor with a dehydrogenation catalyst, to produce para-xylene or toluene.
1. A method of making a compound, comprising:
(a) reacting a C5 or C6 linear monoene with a hydrogen acceptor in the presence of a hydrogen transfer catalyst to produce a C5 or C6 conjugated linear diene; and
(b) reacting said C5-C6 conjugated linear diene with ethylene in a Diels-Alder reaction to produce a cyclohexene having 1 or 2 methyl groups substituted thereon,
wherein said reacting steps (a) and (b) are
(i) carried out as a one-pot reaction in the same reaction vessel; or
(ii) carried out with the same catalyst.
2. The method of claim 1 , wherein said reacting step (a) further comprises:
reacting a C5 or C6 linear alkane with a hydrogen acceptor in the presence of a hydrogen transfer catalyst to product said C5 or C6 linear monoene.
3. The method of claim 1 , wherein said hydrogen transfer catalyst is an iridium, platinum, palladium or nickel hydrogen transfer catalyst.
4. The method of claim 1 , wherein said hydrogen transfer catalyst is an iridium pincer complex catalyst.
5. The method of claim 1 , wherein said C5 or C6 linear diene is selected from the group consisting of 1,3-pentadiene and 2,4-hexadiene.
6. The method of claim 1 , and wherein said diene is hexadiene and is produced at a molar ratio of hexadiene to hexatriene of at least 10:1.
7. The method of claim 1 , wherein said hydrogen acceptor is a C2-C20 alkylene.
8. The method of claim 7 , wherein said hydrogen acceptor is ethylene, propylene, butylene, tert-butylethylene, or said C5 or C6 linear monoene.
9. The method of claim 8 , wherein said hydrogen acceptor is ethylene.
10. The method of claim 1 , wherein said reacting step (a) is carried out at a temperature of from 100 degrees Centigrade to 600 degrees Centigrade, and at pressure of from 100 psi to 7,000 psi.
11. The method of claim 1 , wherein said reacting steps (a) and (b) are carried out as a one-pot reaction in the same reaction vessel.
12. The method of claim 1 , wherein said reacting steps (a) and (b) are carried out with the same catalyst.
13. The method of claim 1 , further comprising the step of:
(c) dehydrogenating said cyclohexene in the presence of a hydrogen acceptor with a hydrogenation catalyst to produce a compound selected from the group consisting of para-xylene and toluene; or
dehydrogenating said cyclohexene in the absence of a hydrogen acceptor with a dehydrogenation catalyst to produce a compound selected from the group consisting of para-xylene and toluene, and optionally with ethyl benzene produced concurrently therewith.
14. The method of claim 13 , wherein said hydrogen acceptor is ethylene, and wherein para-xylene and ethyl benzene are concurrently produced.
15. The method of claim 13 , wherein said reacting steps (a), (b) and (c) are carried out as a one-pot reaction in the same reaction vessel.
16. The method of claim 13 , wherein said reacting steps (a) and (c) are carried out with the same catalyst.
17. The method of claim 1 , wherein said C5-C6 linear monoene is a compound of Formula I:
where R is H or CH 3 .
18. The method of claim 1 , wherein said C5-C6 linear diene is a compound of Formula II:
where R is H or CH 3 .
19. The method of claim 1 , wherein said cyclohexene is a compound of Formula III:
wherein R is H or CH 3 .
20. The method of claim 1 , wherein said C5 or C6 linear monoene is 1-hexene, and wherein said 1-hexene is produced by trimerizing ethylene in the presence of a chromium catalyst.